With increasing development of the modern technologies and the electronic industries, a variety of electronic devices such as computers, notebook computers, mobile phones or digital cameras have become indispensable parts of the human lives. Furthermore, most users may frequently come into contact with computers. By using a mouse, a keyboard or any other peripheral device to operate the computer, the selecting, dragging or circumscribing function through the cursor motion or the typing function through the keyboard may be achieved.
Nowadays, many peripheral devices are developed to replace the mouse, or a keyboard and a mouse are combined together in order to operate the computer. For example, a multiple-cylinder control device is disclosed in U.S. Pat. No. 6,300,938. The surface of the cylinder has a pattern indicative of a resolution. In response to movement or rotation of the cylinder, the sensor outside the cylinder may detect the resolution of the surface of the cylinder, thereby issuing a signal to control the motion of a cursor shown on the display screen. Furthermore, a single-cylinder control device is disclosed in U.S. Pat. No. 6,337,680. The surface of the cylinder also has a pattern indicative of a resolution. Furthermore, a loop means for a pointing device is disclosed in Chinese Patent No. CN 1813235. The loop means is equipped with a friction material and intermediate flexing zones. The surface of the loop means is equipped with strips parallel to the longitudinal axis of the loop means for stiffening the loop means. Moreover, the support layer disposed on the outer surface of the loop means has a considerable thickness change.
However, the above techniques still have some drawbacks. For example, since the pattern indicative of the resolution should be formed on the hard material to achieve the accurate and precise resolution, the fabricating process is very complicated. On the other hand, since the structure for stiffening the loop means is formed on the flexible material, the considerable thickness change is detrimental to the comfort of operating the loop means for a long time.